When will we get our first teaser for the sequel?

There's always the possibility of the Comic-Con teaser being leaked online. But I suspect there won't be an official teaser released until 2016 at the earliest. They might show another teaser at Comic-Con next year though.

I think the count was lower than 100 days from release when G14 got it's first public teaser

I think Legendary will release a teaser sooner than 100 days before release, simply because there has already been one movie and the public has known about the sequel since 2014. There's no point in keeping the sequel as concealed and ambiguous as G14.

I mean there was no real point in them holding off on trailers for G14 since there were multiple trailers shown at a comic con that were never released to the public. Unless a new person is incharge of marketing I don't see any evidence they'll change much.

Id say a concept trailer in comicon 2015, a teser in 2016, a trailer in 2017, and tvspots in 2018 

^I agree, but with a trailer in early 2018.

KINGKAIJUGOJIRA - I would absolutely love to see a trailer in the near future! Alas, I believe we'll have to wait a year or two before we recieve anything to wet our apetites for the sequel. That being said, we can hope for a tidbit or two! :)

Given that the movie is 2018, we're not likely to see a true teaser until 2017 at the earliest. The only official teaser we got of the 2014 movie came in 2013 shortly after the Godzilla Encounter showed up in San Diego. If legendary follows the same marketing pattern for the sequels, we've got a LONG wait ahead for anything official.